1. 10.1-11.1 presentations edited

2. EXAM RESULTS
Average=73
Average = 64

3. Which one of the following statements concerning permanent magnets is false?
A) The north pole of a permanent magnet is attracted to a south pole.
B) All permanent magnets are surrounded by a magnetic field.
C) The direction of a magnetic field is indicated by the north pole of a compass.
D) Magnetic field lines outside a permanent magnet originate from the north pole and end on the south pole.
E) When a permanent magnet is cut in half, one piece will be a north pole and one piece will be a south pole.

4. Which one of the following statements concerning the magnetic force on a charged particle in a magnetic field is true?
A) The magnetic force is a maximum if the particle is stationary.
B) The magnetic force is zero if the particle moves perpendicular to the field.
C) The magnetic force is a maximum if the particle moves parallel to the field.
D) The magnetic force acts in the direction of motion for a positively charged particle.
E) The magnetic force depends on the component of the particle's velocity that is perpendicular to the field.

5. Which one of the following statements best explains why a constant magnetic field can do no work on a moving charged particle?
A) The magnetic field is conservative.
B) The magnetic force is a velocity dependent force.
C) The magnetic field is a vector and work is a scalar quantity.
D) The magnetic force is always perpendicular to the velocity of the particle.
E) The electric field associated with the particle cancels the effect of the magnetic field on the particle.

6. Forces on Charges

7. More Clickering …
A charged particle enters a uniform magnetic field and follows the circular path shown in the drawing.
The charge on the particle is:
A Positive
B Negative
C Neutral
D North
E South

8. Look at the direction of the force and the velocity
Magnetism

9. Magnetism

10. Magnetism

11. Off Angle P
Magnetism

12. The Unit’s Experimental Set-up
Force on a Wire

13. Use the VERTICAL setup as shown here.
Change in
Unit
Plates are optional
but you should try
them.

14. Get To Work!

15. MM*
*More Magnetism
10.2

16. The Magnetic Sector Mass Spectrometer
Detector Array

17. An electrical current is flowing out of the page
An electrical current is flowing out of the page. Looking INTO the current, the magnetic field is
A Clockwise
B Zero
C Counterclockwise

18. A current carrying conductor is oriented as shown in the diagram.
The FORCE on the wire with respect to the diagram is:
A Left
B Right
C In
D Out
E Up or Down N S I

19. A current carrying conductor is oriented as shown in the diagram.
The FORCE on the wire with respect to the diagram is:
A Left
B Right
C In
D Out
E Up or Down N S I v B

20. Two parallel wires have electric currents that are
flowing in the same direction. The two wires will
A Attract
B Repel
C Have no interaction

21. Force on a Wire Carrying a Current in a B Field

22. Magnetic field of long straight conductor –
Magnetism
Placed over a compass, the wire would cause the compass needle to deflect. This was the classic demonstration done by Oersted as he demonstrated the effect.

23. Result r
The permeability constant (μ0), also known as the magnetic constant or the permeability of free space, is a measure of the amount of resistance encountered when forming a magnetic field in a classical vacuum. The magnetic constant has the exact (defined) value µ0 = 4π×10−7 ≈ ×10−6 H·m−1 or N·A−2).
Magnetism

24. Force Between Two Current Carrying Conductors
Magnetism
First wire produces a magnetic field at the second wire position.
The second wire therefore feels a force = Bil

25. Two Wires
Magnetism

26. Today’s Experiment

27. Change in Unit The Experiment Plates are optional but you should try
them.

28. Get to Work

29. How about a QUIZ???

30. Still More Magnetism
L-10.3

31. The Quiz 2
r=a 1
Current
out

32. Klicquer Question PHYSICS Points A, B and C form an equilateral
triangle. Two parallel wires at B and C carry
equal currents into the page. As a result
of these two currents, what is the DIRECTION
of the magnetic field at point A?
A To the right
B To the Left
C Down
D Up
E In or out of the plane of ABC x  A C B

33. Discussion
PHYSICS x  A C B
A - Right

34. Kratos Profile HV-3 Gas Chromatograph & Direct Probe Mass Spectrometer
Description
Medium resolution double focusing (E/B) magnetic sector mass spectrometer with gas chromatograph and direct probe inlets; electron impact and chemical ionization sources.

36. EXAMPLE: Molecular structure and mass spectrum of 1-acetyl-4-(2-pyridyl)piperazine. The mass spectrum was obtained with a Perkin-Elmer ion trap detector.

37. Last Time – Force on a Wire

38. Let’s talk about torque
Current Loops in Magnetic Fields

39. Current Loop
What is force
on the ends??
Loop will tend to rotate due to the torque the field applies to the loop.
Magnetism

40. The Loop (From the top) OBSERVATION Force on Side 2 is out
of the paper and that on
the opposite side is into
the paper. No net force
tending to rotate the loop
due to either of these forces.
The net force on the loop is
also zero,
pivot
Magnetism

41. The other sides t1=F1 (b/2)Sin(q) =(B i a) x (b/2)Sin(q)
total torque on
the loop is: 2t1
Total torque:
t=(iaB) bSin(q)
=iABSin(q)
(A=Area)
Magnetism

42. For a Coil of N Turns t=N(iaB) bSin(q) =NiABSin(q)
DEFINE Magnetic Moment m:

43. Galvanometer
This is a very sensitive instrument and is easily damaged.

44. Another Application: The motor
If the conductor is a loop, the torque can create an electric motor.

45. What were your results last time? was f~bil??
Last Unit:

46. To Work

47. Coils and Lentz
The Old and the New
Magnetism 11.1

48. What the heck are we doing this week?1
We will complete the chapter 2
We will look at Evil Lentz 3
We will complete the current and the next unit! 4
There will be a Friday Quiz

49. Transitions

50. Coils
Company Logo

51. The Magnetic Field in a CoilS N
Yikes … it’s a magnet!!!

52. What Do We do here???
The field inside the coil is just N times the field from a single coil.
The field obtained by adding the fields from each coil separately. Don’t know how, though.
The field cannot be calculated with the tools we currently have.
The field is just another way to reduce our grades!!

53. Ampere to the Rescue! (1775-1836)
Ampere’s Law

55. B=0 l

56. We will now enter The Strange World of Dr. Lentz

57. We will now enter The Strange World of Dr. Lentz
Gauss

58. Lentz’s Law

59. INDUCTION
The movement of the magnet closer to the coil increases the “amount of magnetic field” going through the coil.
This causes a current to develop in the coil.
This process is called INDUCTION.

60. “Amount of Magnetic Field” needs to be defined: Magnetic Flux

61. GENERAL EXPRESSION FOR MAGNETIC FLUX

62. May the flux be with you

63. GRAPHICAL INTERPRETATION OF MAGNETIC FLUX
The magnetic flux is proportional
to the number of field lines that pass
through a surface.

64. Induction
4/21/2017

65. The Magnetic Flux Going Through The Loop:
Add up all of these pieces
that are INSIDE the loop.

66. A triangular loop of sides 3,4 and 5 meters is placed perpendicular to a magnetic field B. The magnetic Flux through the loop is: A 12B B 6B C 3B D 20B E Not enough information is provided

67. Gauss’s law When you change the flux through a conducting loop, the
CURRENT induced into the loop by this change will
flow in such a way to create a flux change that opposes
the changing flux that is causing the current in the first place!

68. Changing F Change any or all of the And the Flux will change! Bi DAifi
Change the SHAPE of the loop
Change the ANGLE that the loop makes with the magnetic field (subset of above)
And the Flux will change!

69. Changing the flux through the loop will change the current
Changing the flux through the loop will change the current. But what way will the current actually flow?

70. which way will the current actually flow?
Answer:
The way that you don’t
want it to!

71. Example of Nasty Lenz

72. today … something new

73. You worked on this unit last time. lets look at the end of the unit…
+ Handout
Don’t calculate the current … just the direction of the
current and explain to the class!

74. WORK ……. let’s do it! Finish unit and start the next one!